1. Field of the Invention
The invention of the present application relates to the field of oil fired burners, and in particular to atomizer nozzles for atomizing fuel oil with an atomizing fluid. Even more particularly, the invention relates to such an atomizer nozzle having a novel construction including an atomizer tip which is economically produced and in which the oil and the fluid are efficiently and effectively brought into contact with one another.
2. The State of the Prior Art
The state of the prior art is exemplified by the teachings of U.S. Pat. No. 5,368,280, which issued on Nov. 29, 1994 and by an article authored by P. J. Mullinger et al. entitled xe2x80x9cTHE DESIGN AND PERFORMANCE OF INTERNAL MIXING MULTIJET TWIN FLUID ATOMIZERSxe2x80x9d, J. Inst. Fuel, 1974 (December), 47, 251-261. However, in spite of the many improvements which have been made in the fuel oil atomization field in the past, many problems still exist. From an economical view point, improvements in operational efficiency are continuously sought.
The present invention provides a high efficiency liquid fuel atomizer which reduces operational and maintenance costs as well as undesirable emissions. Due to its simple construction, the nozzle is also low in initial cost. In accordance with the concepts and principles of the invention, an embodiment of the nozzle may be constructed to include an elongated generally tubular member defining a liquid fuel pre-atomization chamber. This tubular member preferably may have an outer wall that extends at least partially around the chamber, an upstream end adapted for connection to a source of liquid fuel and a downstream fuel delivery outlet. The nozzle may also preferably include structure defining a generally annular pressurized atomizing fluid supply conduit disposed in surrounding relationship relative to the pre-atomization chamber. This structure may preferably include a conduit inlet adapted for connection to a source of pressurized atomizing fluid and a downstream pressurized atomizing fluid delivery outlet. The outer wall of the tubular member may have at least one orifice therethrough which is located so as to intercommunicate the chamber and the conduit so as to permit pressurized atomizing fluid to enter the chamber where it acts to at least partially atomize the fuel and create a first mixture of atomizing fluid and fuel in the chamber. The nozzle also may include an atomizing tip that has at least one internal mixing port arrangement that is in fluid communication with the fuel and fluid delivery outlets for receiving and intermixing therein the first mixture of fluid and fuel from the chamber and additional pressurized atomizing fluid from the conduit so as to further atomize the liquid fuel and create a second mixture of fluid and fuel.
In another preferred embodiment of the invention, a high efficiency liquid fuel atomizer is provided which includes an elongated generally tubular member defining a liquid fuel pre-heating chamber. The tubular member has an outer wall that extends at least partially around the chamber, an upstream end adapted for connection to a source of liquid fuel and a downstream fuel delivery outlet. In this form of the invention, the nozzle may include structure defining a generally annular pressurized atomizing fluid supply conduit that is disposed in surrounding relationship relative to the chamber. Such structure may preferably include a conduit inlet adapted for connection to a source of heated pressurized atomizing fluid and a downstream pressurized atomizing fluid delivery outlet. The nozzle may be constructed such that at least a portion of the outer wall of the tubular member is formed of a heat conductive material. This portion may have an inner surface positioned for being contacted by liquid fuel in the chamber and an outer surface positioned for being contacted by heated pressurized atomizing fluid in the conduit whereby the fuel is heated by transfer of heat from the heated fluid to the fuel through the heat conductive material of the portion. The nozzle may also include an atomizing tip including at least one mixing port arrangement that is in fluid communication with the delivery outlets for receiving and intermixing heated liquid fuel from the chamber and atomizing fluid from the conduit whereby to atomize the heated liquid fuel.
In further accordance with the concepts and principles of the invention, an orifice may be provided through the outer wall. Such orifice may intercommunicate the chamber and the conduit so as to permit the heated and pressurized atomizing fluid to enter the chamber and at least partially atomize said fluid fuel therein.
In still further accordance with the preferred aspects of the invention, the port arrangement in the nozzle tip may be y-shaped and configured to include a first elongated port having an upstream end in fluid communication with the fuel delivery outlet and a downstream end, and a second elongated port having an upstream end in fluid communication with the fluid delivery outlet and a downstream end. The first and second ports may preferably be arranged at an angle and positioned such that the downstream end of the first port intersects with the second port at a location between the ends of the latter. With such an arrangement, the at least partially atomized fuel passing through the first port is intermixed in the second port with atomizing fluid passing through the second port. The atomizing fluid thus further atomizes the fuel and an admixture of atomized fuel and atomizing fluid is discharged from the nozzle tip through the downstream end of the second port. Also with such an arrangement of ports, heated fuel passing through the first port may be intermixed in the second port with atomizing fluid passing through said second port and atomized thereby and an admixture of atomized fuel and heated atomizing fluid may then be discharged through the downstream end of the second port. In addition, when such a port arrangement is employed, the heated and at least partially atomized fuel passing through the first port may be intermixed in the second port with atomizing fluid passing through the second port and atomized further thereby and an admixture of atomized fuel and heated atomizing fluid may then be discharged through the downstream end of the second port.
In a particularly preferred form of the invention, the fuel from the first port may be introduced into the second port as a cone shaped sheet that is positioned for being pierced by the atomizing fluid flowing through the second port. The fuel from the first port may be at least partially atomized and/or heated.
The invention also provides a high efficiency method for atomizing a liquid fuel. In one preferred form of the invention, the method may include providing a liquid fuel and causing the same to flow into and through a pre-atomization chamber. The method may further include injecting a first portion of a pressurized atomizing fluid into the liquid fuel flowing through the chamber so as to at least partially atomize said fuel and provide a first admixture containing atomized fuel and atomizing fluid. In accordance with the invention, the first admixture may then be delivered from the chamber and caused to flow into and through a first elongated port in an atomizing tip connected to said chamber. A second portion of pressurized atomizing fluid may be directed into a second elongated port in the tip and caused to flow through the second port. The first admixture from the first port may be introduced into the second port and caused to become intimately intermixed with the second portion of pressurized atomizing fluid so as to further atomize the fuel and provide a second admixture comprising atomized fuel and atomizing fluid. The second admixture may then be discharged from the tip. In accordance with the particularly preferred aspects of the invention, the liquid fuel may be heated in the chamber.
In a preferred form of the invention, the chamber may be elongated and generally tubular in form and the atomizing fluid may be caused to flow in an annular flow path in surrounding relationship to an outer wall of the chamber. In this form of the invention, the injecting of the fluid into the chamber may be accomplished via an opening provided in the wall.
In accordance with the preferred aspects of the invention, first admixture is introduced into the second port as a cone shaped sheet that is pierced by the atomizing fluid flowing through the second port. In accordance with another preferred aspect of the invention, the ports are arranged at an angle, the second port has an inlet end and an outlet end, and the first port is positioned so as to intersect with the second port at a location between the ends thereof. In accordance with the principles and concepts of the invention, the chamber may preferably be elongated and generally tubular in form and the atomizing fluid may be steam. The steam may preferably be caused to flow in an annular flow path in surrounding relationship to an outer wall of the chamber with the injecting being accomplished via an opening provided in said wall. The heating is accomplished both by intermixing of steam with fluid fuel in the chamber and by heat transfer through the wall.
In accordance with yet a further preferred aspect of the invention, yet another high efficiency method is provided for atomizing a liquid fuel. In this form of the invention, the method includes providing a liquid fuel and causing the same to flow into and through a pre-heating chamber; heating the liquid fuel in the chamber; delivering heated fuel from the chamber and causing the same to flow into and through a first elongated port in an atomizing tip connected to the chamber; directing a pressurized atomizing fluid into a second elongated port in tip and causing the fluid to flow through the second port; introducing the heated fuel from the first port into the second port and causing the same to become intimately intermixed with the pressurized atomizing fluid so as to atomize the heated fuel and provide an admixture comprising atomized fuel and atomizing fluid; and discharging the admixture from the tip.
Preferably, in accordance with the concepts and principles of the invention, the chamber is elongated and generally tubular in form and the atomizing fluid is steam. The steam may be caused to flow in an annular flow path in surrounding relationship to an outer wall of the chamber and the heating may be accomplished by heat transfer through the wall.
In accordance with the invention, two or more of the aspects of the invention described above may be combined in a single atomizer to achieve optimal operational results.